Despite the pomp and ceremony of the cardinals entering conclave, black smoke poured from the Sistine Chapel chimney on the first day of voting, signifying the cardinals had not chosen a new pope.More >>

Despite the pomp and ceremony of the cardinals entering conclave, black smoke poured from the Sistine Chapel chimney on the first day of voting, signifying the cardinals had not chosen a new leader of the Catholic Church. More >>

A new pope has been chosen, but the world has not met him yet. Here are possible frontrunners.More >>

A new pope has been chosen, but the world has not met him yet. Here are possible frontrunners.More >>

(RNN) – Pope Benedict XVI's sudden announcement that he would resign came as a surprise to the world at large, but in hindsight one expert noted that the 85-year-old pontiff may have been giving many indications of his intentions.

His travel had not been scheduled for 2013, and Benedict had visited the graves of his predecessor and of Pope Celestine V, who resigned as pontiff in 1294. (Pope Gregory XII resigned in 1415 to help unify the papacy during a period of division in the Catholic Church).

Citing his "advanced age" as the reason for stepping down, Benedict's last day will be Feb. 28.

"Benedict XVI had visited the grave of Celestine V twice, and had gone to the tomb of the last pope (John Paul II) for prayer, and I think others may have thought it was quaint. But it turns out it may have meant more than we thought of at the time," said Dr. Jeffrey Marlett, professor of religious studies at College of Saint Rose in Albany, NY.

The church expects an orderly transition. Vatican spokesman Federico Lombardi said there will be no risk of "confusion or division arising from his resignation."

Benedict XVI has been a conservative pope, known as a scholar and an intellectual who valued the tradition of the Catholic Church. But he will likely be remembered for forging a new path by resigning. Marlett said Benedict XVI recognizes that although we are able to live longer, are we able to live more ably? Images of John Paul II looking frail and ill dominated the last few years of his life.

The pope who succeeds him will face a situation that is unprecedented in modern times.

"What do you when your predecessor has the office around the block from you? Pope Emeritus 101 - that's the unknown territory. What do we do?" Marlett said. "Everyone previous hasn't had someone to talk with."

In his eight years as head of the Catholic Church, Benedict came under fire for allegations of child abuse by priests, as well as his controversial statements concerning other religions, gay marriage and contraception.

Those issues created obstacles to reviving Christianity in an increasingly secular Europe.

Shortly after his election in 2005, it came to light that during his childhood in Germany, Benedict was a member of the Hitler Youth. His defenders argued that all German children were drafted into the ranks without a choice and remained there until the war ended.

Another Benedict controversy that happened early in his career implicated him in a cover up of two pedophile priests in Germany. But as pontiff he met with victims of abuse to try to move the church forward through the scandal.

Marlett said though it does not diminish the scandal, that some of the thinking in the 1970s was that those committing the wrongdoing could be healed and counseled.

"But people are still hurt, and Benedict XVI said, regardless of who made the mistake, the church is there to try to heal the hurt caused by life and even the church itself. He was willing to say the church caused these things and is willing to heal them," Marlett said.

The "VatiLeaks" scandal involved former papal butler, Paolo Gabriele, who leaked hundreds of Catholic documents and claimed that more than 20 whistleblowers were involved in the operation. The leaks were an attempt to prove there was corruption, power struggles and incompetence at the highest levels at the Holy See.

Marlett said this controversy probably contributed to the stress on this pope's health because he was betrayed by someone he knew.

Benedict's own words often created controversy. He spoke out in 2012 against gay marriage, affirming the need for society to "acknowledge and promote the natural structure of marriage as the union of a man and a woman."

The pope sparked a row with Muslim leaders in 2006 after a speech he gave to university professors during a visit to Germany, where he referred to a Byzantine text that called the teachings of Mohammed "evil and inhuman."

He expressed deep regret afterward, saying, "I am deeply sorry for the reactions in some countries to a few passages of my address at the University of Regensburg, which were considered offensive to the sensibility of Muslims."

In 2008, the pope angered the Jewish community by promoting a new version of the Good Friday prayer for the Jews "to be delivered from darkness."

The version read: "Let us also pray for the Jews: That our God and Lord may illuminate their hearts, that they acknowledge that Jesus Christ is the Savior of all men."

Benedict XVI was an intellectual who put centuries of learning and doctrine into his speeches that got lost in translation in the current, 140-character Twitter world we now live in, Marlett said. The pope's scholarly, nuanced speeches were distilled down and lost their overall meaning.

Despite his conservative nature, Benedict embraced technology. In December, he began using Twitter, where he has 1.5 million followers, to which he received some vitriolic responses to his tweets, and he never engaged in the negativity.

Although Benedict saw his fair share of controversy in his eight years, his time paled in comparison with some of his predecessors.

As pope during the climax of World War II, Pius XII (1939-1958) held a uniquely moral obligation. But anti-Nazi leaders, like Poland's exiled President Wladyslaw Raczkiewicz, were incensed he wouldn't condemn the deportation of Jews from around Italy and other countries.

Pius remained under pressure for much of the war, although historical records show that his Vatican protected hundreds of Italian Jews from being deported. The pontiff may have actually been a co-conspirator in a plot to kill Hitler.

Benedict is the first pope to resign in nearly 600 years. The last was Pope Gregory XII in 1415.

Gregory, who was not the namesake of the Gregorian calendar (Gregory XIII) or chant (Gregory the Great or Gregory II), served from 1406 to 1415. He served as the legitimate pope during a schism in the Catholic Church involving two "anti-popes."

Pope Benedict XIII was supported by the French king, while Pope John XXIII was supported by a renegade ecumenical council, the Council of Pisa.

Gregory, forsaken by most of his cardinals, made a deal to officially resign if the anti-popes followed suit, in order to heal the church. Pope Martin V was elected as the legitimate successor.

Gregory, whose birth name was Angelo Corrario or Correr, was appointed Bishop of Porto and perpetual legate at Ancona, Italy.

Ratzinger chose the name Benedict, which comes from the Latin word meaning "the blessed," in homage to Pope Benedict XV, who was pope during World War I, and Saint Benedict of Nursia, who established the Benedictine monasteries.

According to CNN, the pope is likely to retire to a monastery and devote himself to a life of reflection and prayer.

He was the sixth German to serve as pope, but the first since the 11th century.

A conclave will be called in which the members of the College of Cardinals will gather in Rome and vote up to four times per day until they've elected a new pontiff.

"The pope did not intend to influence the decision of the cardinals who will enter a secret conclave to elect a successor," Federico said. Pope Benedict XVI will retire to Castle Gandolfo during the vote.

Catholics will start Lent with one pope and end with a new pope, who should be selected by Easter, which is March 31. Benedict will go back to his birth name, Joseph Ratzinger, after his resignation.